RESUMEN
METHODS: A cytotoxicity assay for BHD was performed using the MTT assay. Following treatment with BHD, mBHD-1, and mBHD-2 in the presence of lipopolysaccharide (LPS), nitric oxide (NO) secretion was detected in cell supernatants using a NO detection kit. The expression of proinflammatory mediators was detected using RT-PCR and western blotting. To verify the mechanism of mBHD, specific inhibitors of JNK (SP600125) or p38 (SB203580) were used for co-treatment with mBHD, and then the changes in NO and nitric oxide synthase (iNOS) were measured. RESULTS: Both mBHD-1 and mBHD-2 showed greater anti-inflammatory effects than BHD. Both mBHD-1 and mBHD-2 inhibited NO secretion and decreased the expression of IL-1ß, IL-6, TNF-α, and iNOS. Treatment with a p38 inhibitor and a JNK inhibitor in mBHD-1- and mBHD-2-treated cells resulted in inhibition of NO and iNOS. CONCLUSION: We provided the first experimental evidence that mBHD may be a more useful anti-inflammatory than BHD. High concentrations or long-term use of BHD may be harmful to inflammatory status. Therefore, the length of treatment and concentration should be considered depending on the targeted disease.
RESUMEN
Melanin is an effective absorber of light and can extend to near infrared (NIR) regions. In this study, a natural melanin is presented as a photothermal therapeutic agent (PTA) because it provides a good photothermal conversion efficiency, shows biodegradability, and does not induce long-term toxicity during retention in vivo. Poloxamer solution containing melanin (Pol-Mel) does not show any precipitation and shows sol-gel transition at body temperature. After irradiation from 808 nm NIR laser at 1.5 W cm-2 for 3 min, the photothermal conversion efficiency of Pol-Mel is enough to kill cancer cells in vitro and in vivo. The tumor growth of mice bearing CT26 tumors treated with Pol-Mel injection and laser irradiation is suppressed completely without recurrence postirradiation. All these results indicate that Pol-Mel can become an attractive PTA for photothermal cancer therapy.